Children have finely tuned capabilities for detecting when grown-ups say one thing and do another. That's the premise that Heidbreder (I Wished for a Unicorn) and debuting illustrator Mate entertain, with their sun-up to sundown visit to a goofy but loving crocodile family. ""Crocodiles breakfast/ on crocodile food/ where crocodile manners/ are never rude,"" declares Heidbreder. ""They chew and swallow/ their mouths closed tight./ Crocodiles say..."" and with that page-turning cue, readers see the words ""Always be polite!"" dancing on the page while the reptilian family engages in a G-rated bacchanal. Mom Crocodile crams her mouth with a bushel of fruit and several muffins, Dad washes down his vittles with orange juice straight from the pitcher, and their offspring eats the cereal box along with its contents. Although most of the scenes are domestic in nature, the book does follow the youngster to school, where it's clear that when ""Crocodiles say... We follow all the rules!"" they're working from an unconventional set of guidelines. The schoolroom scene shows students chewing bubble gum and overturning furniture. Mate displays the compositional savvy of a seasoned pro; at the same time, her bright, thickly applied acrylics and streamlined, vivacious characterizations emit a kid-like elan-and will certainly remind readers of their own vibrant artwork. Ages 3-5.